Hong H, Johnson P, el-Saleh S C
Department of Chemistry, Ohio University, Athens 45701.
Int J Biol Macromol. 1990 Aug;12(4):269-72. doi: 10.1016/0141-8130(90)90008-x.
Only the 80-kD catalytic subunit of smooth muscle calpain II shows a change in intrinsic fluorescence on binding calcium, but both the 80-kD and 30-kD subunits show fluorescence changes in bound toluidinyl-naphthalenesulphonate as a result of calcium binding. Both subunits also show changes in intrinsic fluorescence in the presence of calmidazolium and felodipine. These studies indicate that both subunits have binding sites for calcium and the calmodulin antagonists, which are probably located in the calmodulin-like domain of each subunit.
只有平滑肌钙蛋白酶II的80-kD催化亚基在结合钙时显示出固有荧光的变化，但80-kD和30-kD亚基在结合甲苯胺基萘磺酸盐时都因钙结合而显示出荧光变化。在存在钙调蛋白拮抗剂和平痛新的情况下，两个亚基也都显示出固有荧光的变化。这些研究表明，两个亚基都有钙和钙调蛋白拮抗剂的结合位点，它们可能位于每个亚基的钙调蛋白样结构域中。
